This paper reports twelve acarine species belonging to eleven genera in five families, associated with Bambusa sp. (Poaceae), in a woody area from São Paulo State, Brazil. Four species of Tetranychidae (Monoceronychus bambusicola, sp.n.. Oligonychus santoantoniensis, sp.n.. Schizotetranychus longirostris, sp.n. and S. paraelymus, sp.n.) are regarded as new. The genus Cheletomimus Oudemans, 1904 (Cheyletidae) is recorded for the first time to South America.